Integrated RF Filters

Abstract

A communications transceiver hosts an assortment of filters that cover a wide frequency span (from audio to RF) and vary greatly in performance, depending on their function. Some of these filters can be easily integrated (at low frequencies) while others have yet to be put on a silicon chip. This causes many problems in transceiver design since it increases the component count — and therefore costs — while it raises the requirements from the other circuits in the system, as will be shown later on. The main reasons that keep certain filters out of the chip include the high frequency of operation, the high required quality factor and the stringent specifications in terms of dynamic range and power dissipation. In Fig. 8.1, the receiver part of a super-heterodyne system is shown.